On the last level I jumped towards one of the moving platforms and hit it near the edge. Maryo fell half way through it and then froze. I pushed the jump button repeatedly and after a couple of seconds he fell.

I'm sure this is similar to the big where if Maryo tries to climb a vine that is on the ground without jumping up on it he goes into climbing mode and slips beneath the ground and gets stuck. I usually just jump onto the vine to avoid this.